My parents periodically email me articles about various scientists who are outspoken global warming skeptics. Usually I ignore them, as I'm aware that in any field, you can find a few nuts, regardless of how strong the consensus view is. This is certainly true in my field (John Hagelin, if he counts as a physicist still). And I'm not prone to believing in conspiracy theories, which is what it looks to me like you'd have to believe in, in order to deny global warming. However, a few days ago they emailed me this article, which claims that less than half of published climate scientists endorse global warming. This is directly contradictory to pretty much everything else I've heard, both in the media and through talking to other academics (and having attended a lecture or two on global warming by climate scientists). I'm putting this out here in the hope that someone knows what the heck they are talking about in this article, whether there is any truth to it, and if so if it is misleading:

The above article is linked off of the US Senate Committee on Environment and Public Works, so it does not appear to be an obscure or extreme right-wing biased source.

The main reason I need comments on this is that I'd like to respond to the email I got, but I don't know enough about global warming science/politics to comment on it. But if it is true, then I think many people should know about it as this is not the impression that most people I know (including myself) have regarding the current consensus. Thank you, livejournal users!

Comments

Meh, I avoid having any very strong opinion on it. The data I've seen suggests that global warming in the sense of a present trend toward increasing temperatures is pretty overwhelmingly supported, but it seems less clear to what extent this is caused by human activities, or that the effects will be as negative as they are often portrayed to be. On the other hand, it is very clear that lots of people on both sides want conclusions they find politically convenient.

The last time I spent a lot of time looking into this, I was in high school. But a few weeks ago I spent a couple of days doing some reading, which refreshed my memory a bit, and I learned some new things. The short answer is that warming is clearly happening. One major question is a number called the "sensitivity", which is the change in temperature brought about by a doubling of CO2 concentration. (Various arguments support that the temperature change should be logarithmic in CO2 concentration, so you don't have to ask doubling relative to what.)

My understanding of the details is pretty limited, but here's a rough overview of what I got out of the reading I did a few weeks ago:

There's a simple calculation of this temperature change, and then there are a number of complicated feedbacks that alter the final answer by an unknown order-one number. Most climate scientists seem to agree that the overall effect of feedbacks is positive. A few argue that feedbacks lessen the contribution, so that the unknown coefficient is smaller than one. It's basically impossible to argue that the coefficient is negative, although some people still try, I think. There's a lot of observation evidence going against that. If the coefficient is roughly one, then it means that the warming we've seen so far is pretty much all we're going to get from the CO2 we've already put in the atmosphere. That would be surprising, since there are expected to be transients and the sensitivity is really measuring an equilibrium change. The more reasonable expectation is that some of the heating has already happened, and some of the effects are currently hidden in transients (e.g. heat in the oceans) and as the planet equilibrates more of this heat will end up in the atmosphere.

It's interesting that some of the earliest calculations of global warming were due to Arrhenius, and agree pretty well with much more sophisticated estimates. One real puzzle is water vapor feedback, and the early estimates were based on assuming constant relative humidity. That assumption apparently turns out to be pretty good, but I don't think anyone quite understands why; it's sort of an emergent conservation law. It comes out of models that don't assume it, and it also matches some observational evidence.

I came away with the sense that the arguments for anthropogenic global warming are solid, though the amount of warming we have left 'in the pipeline' is known only up to rough estimates. Getting a better understanding of the feedbacks seems like an interesting scientific issue, but I don't see it as really relevant for policy at this point. The information we need to make policy decisions is mostly there already.

The really dangerous unknown, I think, is not in the atmospheric science, but rather what will happen to the ice on Greenland and Antarctica as temperatures increase. There are indications that once some ice shelves melt, huge masses of ice might just start rolling off the continents on timescales that are uncomfortably fast, and then there would be a serious problem with sea level rise.

Also, you should be aware that Senator Inhofe is a right-wing religious nut who does his best to gut environmental protections in this country. Anything from the Senate Committee on Environment and Public Works with his name in sight probably is from an extreme right-wing biased source.

Thank you Matt, that was very helpful. Although I suppose none of this helps me understand how or where they are getting these statistics about the number of papers that hold different stances toward global warming. After looking at it closer, I realize I should be calling it a "blog post" not an article, as that's what it was taken from. But as I read it, if what the guy claims is true, then 7% of the papers published on climate between 2004 to 2007 explicitly deny any sort of human effect on climate change (not just that it's a minor effect compared to other things). This is incompatible with everything else I've heard... namely, that that part is basically a fact, not just a consensus. It's harder to tell how strong the "primarily anthropogenic" consensus is. By some estimates, it seems like it's just a slight majority (or even a minority, if you believe this guy), whereas by other estimates it seems like an overwhelming majority.

What's clear is that "Less than half of all published scientists endorse global warming theory" is pure political spin; what it really means is that most of the papers they surveyed aren't directly saying anything about the issue one way or another. Whether there are really as many papers as they say that explicitly deny anthropogenic global warming seems pretty questionable too; if you follow those links you'll see that people have looked up some of those papers and don't agree that they're rejecting the consensus.

I'm too lazy to go digging for more details, but it looks to me like a politically motivated survey that finds what it wants to find.

I guess the biggest question in my mind now is "how much of the CO_2 increase was due to humans". It seems pretty well established that increased CO_2 levels cause increased temperatures. But I've seen at least one conservative source quote that only 3.4% of the overall CO_2 production was from humans. That seems like a fairly negligible amount, if the response is logarithmic. Do you know if this 3.4% figure is disputed?

It's not, which is why I went looking for the reference I posted below. But still, suggesting that all the CO2 we release when we burn things is the explanation for increasing atmospheric CO2 is a pretty obvious guess, no? Luckily people have done the real science to make it more than a guess.

Actually, it is pretty good science if you've got a good explanation sitting right in front of you, and no other forthcoming explanation that seems at all plausible. We notice that atmospheric CO2 levels change dramatically starting about 200 years ago, and wonder what might have caused it. We know that increased industry (which produces CO2) started about 200 years ago. There are very few known geological changes that began 200 years ago. So we go with the obvious best explanation.

The problem with the god hypothesis isn't that the argument is an inference to the best explanation - it's that god isn't even an explanation, because it raises exactly the same question that it's supposed to answer!

Global warming itself is undisputed. As far as I know everyone agrees that the global temperature has risen over the past 150 years (even the most conservative news sources, and the most non-mainstream scientists). Anthropogenic global warming is disputed by some, but there is a pretty strong consensus on it. Those who challenge it are in the small minority, and somewhat ridiculed by the rest of the climate science community. After looking at the responses cocacolaaddict posted, it looks fairly clear to me that the guy who did the counting probably doesn't even understand the abstracts he was reading.

As for whether we can undo it, I think most people figure we have a chance since we had something to do with it in the first place; however, I have seen some people arguing that it's already too late and we might as well just accept it and figure out how to live at higher temperatures instead of trying to stop it.

As for the danger, I think that's the most debatable part. On the one end, some people are predicting catastrophic consequences. But I think most scientists are saying that this part is still uncertain. The consequences may be slight, or they may be bad, or the may be extremely bad. Where the most common opinion is probably somewhere between bad and extremely bad, but with a lot of uncertainty. I think that's why a lot of global warming activists fall back on what they call "the precautionary principle". Which is kind of a fancy way of saying "better safe than sorry". Personally, I tend to think we should also look at economic factors (like how much environmental regulations might hurt the economy) when considering policy. And also taking into account we will have a lot more technology and wealth at our disposal in the future to try to stop the warming or adapt to it.

If there's anyone who almost always knows what he's talking about, it's him.

Ha! Thanks, but I think the corrected version should read: if there's anyone who can always make up something that sounds convincing on the basis of a small amount of half-remembered knowledge, it's him.

I'm pretty sure that the LaRouchies dispute the claim that global temperature has risen over the past 150 years. They might agree that it's warmer now than it was 150 years ago, but I think they also claim that it was warmer still in the 1920s and 1930s, and has cooled since then. So their claim is that there's no trend whatsoever - the temperature has been fluctuating.

Cool, very handy to have an Earth Scientist around when I need one :)3)Along with the increase in concentration, we also see a very blatant skew of the isotopic makeup of atmospheric carbon towards those fossil fuel numbers.

Yeah ok, after the other links and this, I pretty much feel dumb now about calling into question the link between CO_2 increase and burning fossil fuels. I've been trying to find the site where I originally saw that 3.4% number but for some reason I can't find it again. It's amazing how distorted some of the information is out there.

They also harp on the logarithmic response, shortly after, saying "To double the pre-Industrial Revolution warming from CO2 alone would require about 90,000ppmv (9%) but we'd never see it - CO2 becomes toxic at around 6,000ppmv (0.6%, although humans have absolutely no prospect of achieving such concentrations)."

So how do these numbers fit into the rest of what is being said here (or are they just getting the numbers wrong?)

Well, it's just those two particular paragraphs I was wondering about... the one with the heading "But we're responsible for all the carbon dioxide greenhouse effect?" and the one following it, with the heading "Ah, we've added 2.5% to the total greenhouse effect then?" (and mainly, those two particular claims that I quoted). I don't think the rest of the document is all that relevant, although it still might be interesting to go through it and sort out what they are saying and which sort of things they're sweeping under the rug.

"Humans can only claim responsibility, if that's the word, for abut 3.4% of carbon dioxide emitted to the atmosphere annually, the rest of it is all natural"

Watch out for the phrasing here: they aren't saying humans cause 3.4% of the increased CO2, they're saying 3.4% of the total amount emitted to the atmosphere annually. This might be true, if most of what is emitted is taken up by various natural carbon sinks. If the natural amount is in equilibrium, we don't have to emit a large fraction of the total to have a large effect on the final atmospheric concentration.

They also say "humans might be responsible for 25% of the total accumulated atmospheric carbon", which is consistent with 100/380. They just emphasize the "might", when the evidence seems pretty solid.

Maybe I'll get a chance sometime to read through more of the page. From what I've looked at I don't see anything obviously false, just facts that are selectively emphasized or deemphasized....

Also: junkscience.com is run by Steven Milloy, who works for Fox News and has been a paid shill for Philip Morris and for Exxon.

In general, you should watch out for the phrases "junk science" and "sound science": they tend to be used by corporations trying to undermine good research that goes against their financial interests (and by the politicians paid by these corporations). Chris Mooney's book The Republican War on Science is worth reading for the history and politics of things like this.... (It's not only Republicans who are at fault, but they're much worse.)

All those is-es you toss about make this a lot more fundamentalist than it need be.

Consensus = orthodoxy. As long as an orthodoxy exists consensus will exist. As long as orthodoxy exists, it will fight to perpetuate itself.

I can agree with aspects of the theory of global warming and at the same time not endorse global warming theory. Perhaps I see it as arising from a syncretic combination of factors, of which human stupidity only forms a facet - albeit a significant one. Perhaps I see it as something entirely different.

I was going to point to the Oreskes things too, and also to this post, pointing out that probably what's going on is that global warming is such a consensus that a majority of published climate scientists don't have any reason to endorse it. (When was the last time you saw a physics paper that explicitly endorsed the existence of charged particles, or of mass?)